So close and yet so far.For 44-year-old comeback queen Serena Williams, her aching knee joints probably contributed as much to her tight three-set opening-round defeat as the display by her 20-year-old Australian opponent Maya Joint at Wimbledon on Tuesday.There had been no indication of any injury to the 23-time Grand Slam singles champion during the Joint loss.But Serena did not attend the mandatory post-match press conference, instead issuing a short quote through tournament organisers. Players can be fined for skipping media duties but it was revealed on Wednesday that Williams is dealing with a knee problem.A statement from the seven-time Wimbledon singles champion's agent Jill Smoller read: "Serena tweaked her right knee at the end of the first set and was therefore excused from her media obligations by the Wimbledon and WTA medical teams."She left site that night unaided and is doing everything she can to be ready for her doubles match later this week."The mum-of-two, however, could be forced to pull out of the doubles event if her injury doesn’t heal on time. She is due to join forces with sister Venus in the women's doubles first round against Camila Osorio and Solana Sierra on Thursday.Serena and Venus, 46, who were given a wildcard entry into the tournament, have won the Wimbledon doubles six times, with their most recent title coming in 2016.Serena has not won a Grand Slam singles crown since the 2017 Australian Open, while Venus last lifted a major singles trophy at Wimbledon in 2008.Serena said her astonishing comeback was motivated by a desire to play in front of her two young daughters.Her children watched their mother's loss to Joint alongside her husband Alexis Ohanian and Venus in the players' box on Tuesday.Jaydip is a Pages Editor at Gulf News and has sports running in his veins. While specializing in Tennis and Formula 1, he also makes sure to stay on top of cricket, football, golf, athletics and anything related to sports in general.